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Kaul, O.

Paper Title Page
THPCH086 Design of a Local IP Orbit Feedback at HERA-e 2988
 
  • J. Keil, O. Kaul, E. Negodin, R. Neumann
    DESY, Hamburg
 
  At the electron-proton collider HERA it is often observed that the proton emittance growth rate of colliding bunches is larger compared to non-colliding proton bunches. In addition the proton background rates are increasing when the two beams are brought into collision. There are indications that a contribution comes from closed orbit oscillations of the electron beam at the two IPs. In the arcs of HERA-e oscillation amplitudes of 100-200 micrometer with frequencies of 2-15 Hz and harmonics of 50 Hz are observed. In order to stabilize the orbit at the IPs in both planes a local digital orbit feedback system with a bandwidth of more than 20 Hz has been developed. The beam position at the IPs is measured with BPMs using dedicated electronics. The four local orbit bumps are produced by air-coil steerer magnets. The data are transmitted using SEDAC field bus lines to a central PC, which is used for the computation of the correction.